Spring's progress continues to be rather fitful this year in Alaska. Much of the state has been unusually wet for the time of year in recent weeks, and temperatures have become decidedly cooler than normal again in much of the south. A very vigorous Bering Sea trough is to blame, along with substantially cooler than normal water temperatures in the eastern Bering Sea - the latter being a lingering reflection of the expansive winter sea ice. Here's a recent SST anomaly map:
Interestingly, the PDO index is drifting into more negative territory again, despite the fact that El Niño is developing rapidly in the equatorial Pacific.
The 30-day precipitation anomaly map shows a widespread and significant wet signal across Alaska - see below (NWS data, estimated). Of course, it's usually a rather dry time of year, so the actual amounts are not enormous in most interior and valley locations; but it's a notable statistical anomaly. Anchorage, for example, is running at record wet so far for the April-May period, with just over 3 inches of liquid-equivalent precipitation. The record for the two-month total is 3.29" in 2019.
A temperature chart from Homer illustrates how warmth has been generally lacking in recent weeks. This morning was especially chilly, with many locations near or below freezing across the Kenai Peninsula and farther afield.
Yesterday morning Fairbanks also dropped to 32°F, the latest freeze at the airport in 18 years.
A notable exception to the cool weather pattern has been in the Arctic northwest; Kotzebue was extremely warm for the time of year last weekend, breaking daily record high temperatures.
Here's the 500mb height (mid-atmosphere pressure) anomaly in the last 14 days, expressed in terms of standard deviations departure from normal:
And the 850mb temperature anomaly:
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